Activation of Melanocortin Receptors MC₁ and MC₅ Attenuates Retinal Damage in Experimental Diabetic Retinopathy

Figure 4

FAG performed at baseline (nondiabetic) and after 8, 12, and 16 weeks from diabetes induction after the intravitreal injection of the MC₁ receptor antagonist AGRP, and the MC₅ receptor antagonist PG20N. At baseline no vascular alterations were present 8 weeks following diabetic induction, FAG depicted an increased vascular tortuosity with hyperfluorescent area due to the presence of a venous loop in the retinal inferior nasal area. The first retina damage appears 8 weeks following diabetic induction and was characterized by an extensive hyperfluorescent area of vascular leakage. At 12 and 16 weeks this hyperfluorescent area was extended with progressive dye diffusion. The number of mice for each group was nondiabetic mice and 8 diabetic mice with retinopathy. VL = venous loop.